Red-tailed Hawk

The Red-tailed hawk is Fermilab's
most common raptor. It is a year-round resident and summer breeder.
Up to eight pairs have nested on the lab grounds in one year,
and up to 30 birds have been recorded in a single winter day.

Red-tailed hawks are birds of prey, or raptor. Like falcons
and other hawks, they have strong feet, razor-sharp claws, or
talons, and a hooked bill. The birds use these body parts like
weapons to strike, stab, and rip prey. They kill not for fun or
sport, but to survive. Mature birds of prey are at the top of
their food chain and have few natural predators. Their main enemies
are pollution and loss of habitat.

The Red-tail belongs to a group of hawks called buteos, whose
members have broad wings and short tails. They are fairly easy
to see because they spend much of their time soaring and perching
in open areas. The major identifying factor is its red tail. If
you are lucky, you may see one sitting on the ledge outside the
east window on the 15th floor of Wilson Hall - one of their favorite
perches!

Hawks start their day by stretching, casting pellets, defecating,
and preening their feathers. Soon they leave the roost or nest
site and begin to hunt. Most hawks eat just about any animal,
such as small mammals, birds, and snakes. The buteos tend to swoop
down upon their prey which they kill with their talons. At the
end of the day the red-tail returns to its roost, usually a favorite
tree, cliff or other elevated perch.

A pair of breeding hawks builds a large stick nest on a rock
ledge or a sturdy tree branch. The female incubates two to four
eggs for about one month. After the young hatch the male provides
most of the food while the female cares for the chicks at the
nest. By fall, the young birds are as large as their parents,
but duller in color. They are fully mature and ready to breed
by their second year.

Birds of prey have
extremely sharp sight, up to eight times sharper than our eyesight.
Hawks have an overlapping field of view of 30-50 degrees for binocular
vision, and an overall field of view of about 150 degrees. The
field of view of the two eyes - the area that each one can see
- over-lap, so the brain receives two different sets of messages
about the same part of the picture. This allows the bird's brain
to work out distance and speed, which is very important for catching
prey.

Raptors need to eat large quantities of food for their size
because as much as 30% of their food may be made up of indigestible
feathers, fur, or bones. This indigestible material is regurgitated
sometime after the meal in the form of a pellet. The contents
of the pellets may vary at different times of the year, depending
upon what prey is available.

The feet are very powerful. Hawks have three toes pointing
forward and one pointing backwards. The inside toe and the hind
toe are usually stronger than the others, with larger claws. These
toes are used to grip the prey, while the middle and outer toes
are used to balance the foot when it is walking or perching. The
claws can also be used to kill prey by piercing a weak spot, or
by crushing it.

Watch carefully as you walk or drive through Fermilab and you
may see a Red-tailed hawk perched on a street light, road sign,
or tree branch, or soaring gracefully through the air.